[media] v4l: omap4iss: Report device caps in response to VIDIOC_QUERYCAP

Set the v4l2_capability capabilities and device_caps fields correctly.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>